Transcript Front End for MAP Neutrino Factory/Collider rf considerations David Neuffer May 29, 2014

Front End for MAP Neutrino Factory/Collider
rf considerations
David Neuffer
May 29, 2014
1
Outline
 Previous baseline was 200 MHz (IDS nu Factory)
 Rf, power req.
 Front End for MAP NF/MC 325 MHz
 Bunch train shorter than IDS …
 With Chicane/Absorber
 Current baseline
• Use short taper
 Variations under study
2
325MHz System “Collider”
p
FE Target
π→μ
 Drift
Solenoid
Drift
Buncher
Rotator
Cooler
14.75m
m
~42 m
~21.0 m
~24.0 m
~80 m
 20T 2T
 Buncher
 Po=250MeV/c
 PN=154 MeV/c; N=10
 Vrf : 0 15 MV/m
• (2/3 occupied)
 fRF : 490 365MHz
 Rotator
 Vrf : 20MV/m
• (2/3 occupied)
 fRF : 364 326MHz
 N=12.045
 P0, PN245 MeV/c
 Cooler




245 MeV/c
325 MHz
25 MV/m
2 1.5 cm LiH absorbers
/0.75m
3
325 Collider Update w/Chicane/Absorber
Chicane + Absorber
p
π μ
FE
Targ Solenoid
15m drift
et
+13m chicane
6 m +30.1 m drift
0.1 m
Be
Drift
Buncher
~22m
~21m
Rotator
 Add 30 m drift after chicane
*6.5
m  +15°,-15º
 Add chicane + absorber
•
•
particle 1-283 MeV/c
particle 2-194 MeV/c
•
•
•
10 cm Be
particle 1-250 MeV/c
particle 2-154 MeV/c
•
Pref = 245 MeV/c
 absorber at 41m
 Bunch (N = 12) 015 MV/m: 496 365 MHz
 Rotate (N=12.045 )– 20 MV/m: 365  326.5
MHz
 Cool -325 MHz -25 MV/m
24 m
Cooler
~80 m
SREGION
! bentsol
6.5 1 1e-2
1 0. 1.0
BSOL
1 2.0 0.0 1 0.283 0.0 0.058181
0.0 0.0 0.0 0. 0. 0. 0. 0.
VAC
NONE
0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
ICOOL results
 325 “muon collider” with chicane absorber
 with added drifts between chicane and absorber
• ~30 m
 ~ 0.105 μ/p  but smaller emittance beams
• scraped to better fit?
 Change to shorter taper
 15 m  6 m
 (Hisham) slight improvement in throughput (~ 5%)
 We are using Hisham’s more recent distributions
• Gains ~ 5-10%
• Total is now ~ 0.115 μ/p (in baseline ICOOL simulation units)
 Better Rotator/Cooler match (Diktys)
 +5%
 Cooler will be replaced by better 6-D cooler (Alexahin)
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Compare 325 w chicane vs old 200
High P cutoff is ~700 MeV/c (from ~500 MeV/c)
1.0 GeV/c
z=38m
0
z=137m
z=255m
6
Rf cavity
Concept
design
construction
operation
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MAP rf properties (~ MICE rf)
 Assume pillbox, Cu walls
 Compare with MICE rf
 Q = ~58000
 a=0.574m, L=0.5, f=200MHz
 Tt=0.83
 P0 = 1.35 MW at 10MV/m
 f=200MHz, L=0.5m,
E0=10MV/m
 U0 = 62J, Tfill = 63.7μs
 P0 = 3MW at 15MV/m
MICE rf
parameters
Value
Radius (mm)
610
Length (mm)
430
RT2 (M/m)
22
Power needed
(16MV/m)
4MW
Quality factor, Q0
54,000
Q0 
2.405 Z0
1
2( f rf 0 ) 2 (1  La )
Rs   Cu  0 f 0
2
E
U 0   0 L a 2 0.522 0
2
P0 
 Rs 0.5192 E02 a( L  a)
Z02
sin
Tt 
 
 f rf L
c
 f rf L
c
T fill  Q0
ln(2.0)
 f rf
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rf
IDS RF requirements
 Buncher


37 cavities (13 frequencies)
13 power supplies (~1—3MW)
 RF Rotator



56 cavities (15 frequencies)
12 MV/m, 0.5m
~2.5MW (peak power) per cavity
 Cooling System – 201.25 MHz
 100 0.5m cavities (75m cooler), 15MV/m
 ~4MW /cavity
Front End
section
Length
#rf
cavities
frequencies
# of
freq.
rf gradient
rf peak power
requirements
Buncher
33m
37
319.6 to
233.6
13
4 to 7.5
~1 to 3.5 MW/freq.
Rotator
42m
56
230.2 to
202.3
15
12
~2.5MW/cavity
Cooler
75m
100
201.25MHz
1
15 MV/m
~4MW/cavity
Total drift)
~240m
193
29
~1000MV
~550MW
Magnet
Requirements:
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rf
Rf Buncher/Rotator requirements
 Buncher -21m


37 cavities (14 frequencies)
13 power supplies (~1—3MW)
 RF Rotator -24m



64 cavities (16 frequencies)
20 MV/m, 0.25m
~2 MW (peak power) per cavity
 Cooling System – 201.25 MHz
 200 0.25m cavities (75m cooler), 25MV/m
 ~4MW /cavity
Front End
section
Length
#rf
cavities
frequencies
# of
freq.
rf gradient
rf peak power
requirements
Buncher
21m
37
484 to 365
14
0 to 16
0—1.34 MW/cavity
Rotator
24m
56
364to 326
16
20
~2.4 MW/cavity
Cooler
75m
200
325
1
25 MV/m
~3.7MW/cavity
Total
df+bxr+rttr
~134m
93
30
~500MV
140MW
10
First result on discretization
11
Dependence on rf gradient
 With same cooling channel
 25MV/m IDS 4-D cooling
 Change Buncher/Rotator
peak rf voltage
 0 –25 MV/m
0.14
0.12
0.1
0.08
0.06
0.04
 Longer bunch train
captured with larger V’
0.02
0
0
5
10
15
20
25
20 MV/m
0 MV/m
10 MV/m
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Dependence on Bfinal
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Summary
 We are studying 325 MHz based front end
 produces more bunches in same length bunch train than 200 MHz
 requires more bunches to be recombined ~12  21
• more difficult … ?
• HCC recombiner ?
 Including chicane/absorber
• Improved matching
 Would like to fit more μ in fewer bunches
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Current Status
P5 process:
P5 Result:
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Supplemental slides
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325 (w chicane/absorber)
 ~60 m long bunch train
1.0 GeV/c
 ~60 325 MHz buckets
0m
 For collider choose “best 21
0.0 GeV/c
bunches “
 (~19m)
65m
 Includes ~2/3 of captured
μ’s
 many are lost
 21bunches are recombined
to 1 in collider scenario
 It is more difficult to
recombine 21 than 12
 Would like to extend
acceptance or generate
shorter train
93m
~ end of rotator
131m
~ After ~80m
215m
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P5 result
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